Elevated Circulating Lactate Levels and Widespread Expression of Its Cognate Receptor, Hydroxycarboxylic Acid Receptor 1 (HCAR1), in Ovarian Cancer

Background: Augmented glycolysis in cancer cells is a process required for growth and development. The Warburg effect provides evidence of increased glycolysis and lactic acid fermentation in cancer cells. The lactate end-product of glycolysis is receiving growing traction for its role as a cell signalling molecule. Ovarian cancer (OvCa) is also characterised by altered glucose metabolism. We aim to explore circulating lactate levels in patients with high-grade serous OvCa (HGSOC) and to elucidate the expression of the lactate receptor hydroxycarboxylic acid receptor 1 (HCAR1) in OvCa. Methods: HCAR1 expression was detected in patient biopsy cores using immunohistochemistry, while lactate was measured from whole blood with a Biosen-C line clinic measuring system. Results: We noted significantly elevated lactate levels in OvCa patients (4.3 ± 1.9 mmol/L) compared with healthy controls (1.4 ± 0.6 mmol/L; p < 0.0001), with an AUC of 0.96. The HCAR1 gene is overexpressed in OvCa compared to healthy controls (p < 0.001). Using an OvCa tissue microarray (>75% expression in 100 patients), high protein expression was also recorded across all epithelial OvCa subtypes and ovarian normal adjacent tissue (NAT). Conclusions: Lactate monitoring is a simple, cost-efficient test that can offer point-of-care results. Our data suggest that the potential of circulating lactate as a screening biomarker in OvCa merits further research attention.

Inflammatory and diabetic conditions trigger SHP2 tyrosine phosphatase expression and subsequent aberrant activation of primary human monocytes

Purpose

Atherosclerosis is an inflammatory process that is particularly accelerated in diabetics, leading to increased incidence of cardiovascular diseases such as CAD and PAD in diabetic patients. Monocytes are the main component of atherosclerosis development. SHP-2 tyrosine phosphatase has been identified as an important regulator of monocyte function. The present study therefore aims to investigate the regulation of SHP-2 in inflammatory and diabetic conditions.

Methods

Primary human monocytes were isolated from the peripheral blood of type 2 Diabetes mellitus (T2DM) patients and healthy individuals. Monocytes were incubated with pro-inflammatory cytokine TNFa. For diabetic conditions, monocytes were incubated with methylglyoxal (MG), a highly reactive side product of glycolysis, or Receptor for advanced glycation end product (RAGE) ligand AGE-bovine serum (AGE-BSA). Monocyte migration was studied with Transwell migration assays. Expression of important molecules was investigated with Western Blot, RT-qPCR or FACS. Pharmacological inhibitors for SHP2, RAGE or NFκB were used.

Results

First, we could detect a significant correlation between SHP-2 mRNA and TNFa levels in T2DM monocytes in comparison to monocytes from healthy individuals. In line with that, incubation of monocytes with TNFa lead to an enhanced expression of SHP-2. Co-incubation with NFκB-inhibitor blocked TNFa-induced SHP-2 upregulation. Interestingly, incubation of monocytes with methylglyoxal caused increased release of TNFa and also augmented expression of SHP-2, indicating a pro-inflammatory effect of diabetic conditions.

Moreover, AGE-BSA treatment induced enhanced SHP-2 expression, reflecting an inflammatory-independent pathway which regulates SHP-2 additionally. This could be supported by the observation that pharmacological inhibition of RAGE attenuated both AGE-BSA and MG-induced SHP-2 activation. On a functional level, increased expression of SHP-2 in each treatment resulted in a pro-migratory phenotype that could be completely reversed by inhibition of RAGE, respectively. Fittingly, monocytes from T2DM patients showed increased migration, which normalized to an ordinary level after application of a SHP-2 inhibitor.

Conclusions

The present results reveal a new mechanism for accelerated atherosclerosis development in diabetic patients. MG and advanced glycated end products, as crucial components of the diabetic milieu, lead to increased expression of SHP-2 via the RAGE-NFkB signalling axis. Interestingly, this diabetic environment causes an increased inflammatory response through the release of TNFa cytokine, which itself leads to enhanced SHP-2 expression through activation of the NFkB transcription factor. Finally, by pharmacological inhibition of each component in this outlined SHP-2 regulatory pathway, we were able to prevent the pro-migratory activation of monocytes, offering a new approach to the treatment of diabetes-induced atherosclerosis.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): IZKF SEED Project 14/20

Monocyte and endothelial dysfunction induced by hyperglycemia is reversed by Empagliflozin mainly through glucose-transport independent mechanisms

 

Type II Diabetes mellitus (T2DM) leads via hyperglycemia (HG)-associated inflammation and oxidative stress to vascular cell dysfunction. The EMPA-REG trial revealed a reduction of cardiovascular mortality in T2DM patients by Empagliflozin, a sodium-glucose co-transporter-2 (SGLT-2) inhibitor. SGLT-2 is expressed on monocytes and endothelial cells (EC), therefore the aim of this study was to investigate the potential role of Empagliflozin for glucose transport regulation and improvement of HG-induced dysfunction of monocytes and EC.

HUVEC and HCAEC were used as EC model cells. Primary human monocytes were isolated from T2DM patients and healthy controls. The cells were exposed to HG conditions in vitro in presence of 40 or 100 ng/ml Empagliflozin. Using RT-qPCR and FACS, expression levels of SGLT-2 were analysed. Glucose uptake assays were performed with a fluorescent derivative of glucose, 2-NBDG. To measure reactive oxygen species (ROS) accumulation, we used the H2DFFDA method via FACS and fluorescence microscopy. Monocyte and EC chemotaxis was analysed using modified Boyden chamber assays.

We could prove an expression of SGLT-2 in primary human monocytes and EC. The transcripts of SGLT-2 in T2DM monocytes did not show a difference. SGLT2-levels in monocytes and EC were not altered by HG. In presence of GLUT inhibitor in vitro glucose uptake assays revealed the ability of SGLT-2 inhibition to mildly supress the glucose uptake, whereas uptake by monocytes and EC remained comparable. Nevertheless, in presence of Empagliflozin HG-induced ROS accumulation in monocytes (1.3-fold, p=0.021) and ECs (1.5-fold, p=0.003) was reduced. HG monocytes and EC readily exhibited an impaired chemotaxis behaviour. Treating the cells in HG with Empagliflozin reversed the PlGF-1 resistance phenotype of HG monocytes (1.4-fold, p=0.002). Comparably, Empagliflozin was able to rescued the blunted VEGF-A responses of HG ECs (1.35-fold, p=0.028), which could be ascribed to restoration of VEGFR-2 receptor levels on the EC surface. Most of the aberrant phenotypes exhibited by HG monocytes and EC were entirely recapitulated by induction of oxidative stress. We could mimic these effects of Empagliflozin using the general antioxidant N-acetyl-L-cysteine (NAC).

Our study reveals a beneficial role of Empagliflozin for reversing HG-induced vascular cell dysfunction. The expressed SGLT-2 on monocytes and EC does not serve as primary glucose transporter. So it is highly to speculate that HG-mediated enhanced glucotoxicity in those cells is not prevented by Empagliflozin through inhibition of glucose uptake itself. Reduction of oxidative stress by Empagliflozin was revealed as central mechanism for an improved function of HG monocytes and EC in vitro. Finally, we conclude that antioxidant properties of Empagliflozin reverse vascular cell dysfunction independently of glucose transport. This is likely to support the beneficial effect of Empagliflozin in cardiovascular disease.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Medical Faculty, University of Münster, Germany

Primary human monocytes are stimulated in a pro-atherosclerotic manner in hyperhomocysteine conditions by attenuated PTEN phosphatase function

Purpose

Monocytes are essential for atherosclerosis and hereby crucial for the detrimental consequences of cardiovascular diseases like coronary heart disease. Interestingly, homocysteine (HCY) was identified as an idependent risk factor for atherosclerosis development. However, the specific implication of HCY on monocytes has not yet been clarified and was therefore investigated in the present study.

Methods

Primary human monocytes, isolated from peripheral blood through the immuno-magnetic method, were treated with a clinically relevant dose of 400 μM HCY for 24 hours. Monocyte migration was investigated with transwell migration assays. Adhesion to inflamed endothelium (HUVECs) was studied under static and physiological flow conditions. Expression of relevant molecules was quantified with Western Blot, RT-qPCR and FACS. 5-azacytidine (AZA) was used to inhibit DNA methyltransferase 1 (DNMT1) and SF1670 to inhibit PTEN.

Results

First, we studied monocyte migration phenotype. Under hyperhomocysteine conditons monocytes revealed elevated chemokinesis and enhance chemotaxis towards MCP-1. In addition, monocytes show a pro-adhesive phenotype under HCY treatment which was indicated by heightened adhesion to inflamed endothelial cells, both in static and physiological flow conditions. These data could be sustained by observation of HCY-induced augmented expression of adhesion molecule CD11a on primary human monocytes. Interestingly, we observed decreased PTEN phosphatase function and activity in HCY-treated monocytes, which was reflected downstream in increased activation of AKT at serine 473. Based on these data, it was also possible to induce the pro-migratory phenotype in monocytes by pharmacological inhibition of PTEN alone. Since HCY can modify the methylation status of PTEN and hereby regulates its expression, we inhibited DNMT1 with AZA which could prevent downregulation of PTEN expression by HCY treatment. In addition, through inhibition of DNMT1 HCY-induced aberrant migration and adhesion was rescued. In line with that, HCY-induced pro-migratory and pro-adhesive phenotype was also rescued by co-treatment with the cofactors (30 μM Vitamin B12 and 3 μM folic acid) responsible for homocysteine to methionine catabolism due to normalized PTEN expression.

Conclusions

The present work deciphers a previously unknown mechanism how an increased concentration of HCY induces a pro-atherosclerotic activation of monocytes.

Accumulation of HCY leads to a methylation-dependent inactivation of PTEN phosphatase. This subsequently causes increased phosphorylation of AKT at serine 473, which results in an augmented migration behaviour of monocytes. At the same time, we were able to reduce HCY-induced aberrant monocyte activation by inhibiting DNTM1 or by interfering with HCY metabolism by adding vitamin B12 or folic acid. In summary, these findings provide a new approach to reset pro-atherosclerotic monocytes in hyperhomocysteinemic conditions.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): IZKF SEED Project 14/20

Induction of RAGE-NFkB signalling axis enhances SHP-2 tyrosine phosphatase expression resulting in deviant activation of diabetic monocytes

Purpose

Aberrant activation of Type 2 Diabetes mellitus (T2DM) monocytes is an important pathomechanism leading to restricted arteriogenesis and augmented atherosclerosis, hereby, accelerating CAD and PAD. Tyrosine phosphatase SHP-2 was found to be upregulated in T2DM-monocytes. This study aimed to identify the pathways regulating SHP-2 expression in T2DM-monocytes.

Methods

Primary human monocytes were isolated from the peripheral blood of T2DM patients and healthy individuals. Monocytes were incubated with Methylglyoxal (MG), a highly reactive side product of glycolysis, Receptor for advanced glycation end product (RAGE) ligand AGE-bovine serum (AGE-BSA) or TNFα for 24 hours. Transwell migration assays were used to analyse the migratory potential of monocytes. Western Blot, RT-qPCR and FACS were performed to quantify the expression of relevant molecules. Pharmacological inhibitors were used to study functional relevance of the RAGE-NFκB-SHP-2 signalling axis.

Results

Significantly enhanced SHP-2 expression was detected in monocytes, which were incubated with TNFα, MG or AGE-BSA, respectively. Co-incubation of these molecules with NFκB-inhibitor blocked SHP-2 upregulation. Pharmacological inhibition of RAGE reversed the MG or AGE-BSA induced SHP-2 expression and activity in monocytes. RAGE expression on monocytes was upregulated after the incubation with MG or AGE-BSA, consistent with enhanced RAGE mRNA levels in T2DM monocytes. Besides, we also detected elevated SHP-2 transcripts in monocytes of T2DM patients which was more pronounced in monocytes with augmented TNFα expression. Furthermore, MG and AGE-BSA provoked the enhanced migration of monocytes which could be significantly reduced after the application of an allosteric SHP-2 inhibitor. Interestingly, pharmacological inhibition of RAGE in these conditions alone was sufficient to block the elevated monocyte migration. Moreover, monocytes isolated from T2DM patients revealed a comparable pro-migratory phenotype, which was completely restored after the pharmacological inhibition of SHP-2.

Conclusions

This study identified the upstream signalling mediators that contribute to SHP-2 dependent monocyte activation in T2DM conditions. Glucose metabolite (MG) or RAGE ligand (AGE-BSA) alone were sufficient to induce a pro-migratory phenotype in monocytes by upregulating SHP-2. Of note, an inflammatory state seems to accelerate this effect since enhanced TNFα levels were found to be positively correlated with the augmented SHP-2 expression. Moreover, we identified the RAGE-NFκB signalling axis through which the SHP-2 upregulation is conveyed when augmented accumulation of glucose metabolites occur. These findings reveal a basis for potential new therapeutic approaches to prevent accelerated CAD and PAD in diabetic patients since independent pharmacological inhibition of every step in the RAGE-NFκB-SHP-2 axis was sufficient to reset the aberrant monocyte activation.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Interdisciplinary Center for Clinical Research of the Medical Faculty of the University of Münster

Reference values for the 12 minute walk test in McArdle patients

The maximum distance achieved on a modified 12 min walk test (12MWT) is a well-established measure in McArdle disease glycogen storage disease type V (GSDV). Age, height, body mass and gender are known predictors of walking distance in other patient groups. Reference values to correct for these predictors are necessary for comparisons between individuals. To date, there has not been a systematic investigation of these predictors in the 12MWT in GSDV. This study explores the contribution of these predictors on distance achieved in GSDV. Data, included maximum distance walked, age, gender, height and body mass, was collected from 103 GSDV patients who underwent 12MWT between 2011 and 2017. Analysis showed a significant correlation between distance achieved and height, age, body mass and gender. Multiple linear regression analysis revealed a model accounting for 29.7% of variance (R = 0.545, R² 0.297, adjusted R^{2 0}.269). Gender was not significant after height, age and body mass were entered into the regression analysis. This is the first study to report the contribution of non-disease related factors on distance achieved on the 12MWT in the GSDV population. The reference values generated will allow for improved monitoring and assessment of GSDV patients in clinical and research settings.

Results of an open label feasibility study of sodium valproate in people with McArdle disease

McArdle disease results from a lack of muscle glycogen phosphorylase in skeletal muscle tissue. Regenerating skeletal muscle fibres can express the brain glycogen phosphorylase isoenzyme. Stimulating expression of this enzyme could be a therapeutic strategy. Animal model studies indicate that sodium valproate (VPA) can increase expression of phosphorylase in skeletal muscle affected with McArdle disease. This study was designed to assess whether VPA can modify expression of brain phosphorylase isoenzyme in people with McArdle disease. This phase II, open label, feasibility pilot study to assess efficacy of six months treatment with VPA (20 mg/kg/day) included 16 people with McArdle disease. Primary outcome assessed changes in VO₂peak during an incremental cycle test. Secondary outcomes included: phosphorylase enzyme expression in post-treatment muscle biopsy, total distance walked in 12 min, plasma lactate change (forearm exercise test) and quality of life (SF36). Safety parameters. 14 participants completed the trial, VPA treatment was well tolerated; weight gain was the most frequently reported drug-related adverse event. There was no clinically meaningful change in any of the primary or secondary outcome measures including: VO₂peak, 12 min walk test and muscle biopsy to look for a change in the number of phosphorylase positive fibres between baseline and 6 months of treatment. Although this was a small open label feasibility study, it suggests that a larger randomised controlled study of VPA, may not be worthwhile.

The need for biochemical testing in beta-enolase deficiency in the genomic era

Glycogen storage disease type XIII (GSDXIII) is a very rare inherited metabolic myopathy characterized by autosomal-recessive mutations in the ENO3 gene resulting in muscle β-enolase deficiency, an enzymatic defect of the distal part of glycolysis. Enzyme kinetic studies of two patients presenting with exertion intolerance and recurrent rhabdomyolysis are reported. Next generation sequencing confirmed patient 1 was homozygous for p.E187K in ENO3, while patient 2 was homozygous for p.C357Y. ENO3 variants pathogenicity was confirmed by functional studies in skeletal muscle. p.E187K caused extremely low total enolase activity. p.C357Y was associated with a higher level of residual activity but kinetic studies showed a lower maximum work rate (V max). This study illustrates that GSDXIII may be caused by either null mutations leading to β-enolase deficiency or by mutations that alter the enzyme's kinetic profile. This study highlights the importance of carrying out functional studies as part of the diagnostic process following the identification of variants with next generation sequencing.

3307Impaired reverse transendothelial migration capacity governs the enhanced abluminal accumulation of diabetic CD14+ monocytes

Background

Chronic inflammation drives atherosclerosis. Monocyte recruitment and accumulation in the tissues contributes to chronic inflammation and is an important aspect of the pathobiology of atherosclerosis. Diabetes mellitus (DM) is a leading cardiovascular predisposing to the development of atherosclerosis. Monocytes represent the largest cell-population in the atherosclerotic plaque. However, the mechanisms that drive the accumulation of monocytes in the plaques are not clearly understood.

Purpose

The aim of this study is to understand the hyperglycemia/diabetes-induced changes in the transendothelial and reverse transendothelial migration processes of monocytes under physiological flow conditions and to characterize the underlying mechanisms.

Methods

Monocytes isolated from healthy donors by negative selection were conditioned in hyperglycemic or normoglycemic conditions for 48 hours. These monocytes or monocytes from type 2 diabetes mellitus (T2-DM) patients or from non-diabetic controls were allowed to interact with TNFα -activated HUVEC-monolayer. Experiments were performed under flow conditions found in post-capillary venules. Analysis of migration was performed using Fiji J software. Expression of molecules involved in transmigration and reverse migration was measured using FACS.

Results

Monocytes from T2-DM patients and hyperglycemia-conditioned cells revealed a significantly reduced transendothelial migration capacity. Even though these monocytes adhered to the HUVEC monolayer, only few of them transmigrated. Moreover, the transmigrated cells from diabetic patients and hyperglycemia-conditioned cells accumulated in the ablumen after transendothelial migration. Time in the ablumen was prolonged and there was a significant reduction in the reverse transendothelial migration. Expression levels of chemokine receptors, which had been shown to be essential for transendothelial migration process, were reduced in diabetic monocytes.

Conclusion

Our results revealed for the first time that the enhanced diabetic monocyte accumulation in the albumen is not secondary to the elevated transmigration through the endothelium. Instead, the accumulation of monocytes in the vessel wall is due to the direct consequence of dysfunctional reverse transendothelial migration. These novel findings could explain the underlying reasons leading to the elevated inflammatory monocyte accumulation, chronic inflammation and subsequent atherosclerosis development in T2-DM patients. Our results highlight the importance of restoring the reverse transendothelial migration capacity of monocytes to reduce monocyte accumulation and atherogenesis in the diabetic environment.

‘Never call me a mercenary’: Identity work, stigma management and the private security contractor

Organisation studies has paid little attention to the contemporary private security industry, despite its enormous recent growth as a supplement to or replacement for state military services in theatres of conflict. To address this neglect, we investigate the workers at the heart of the industry: private security employees or contractors. Amidst widespread and extremely critical media coverage of their activities, we consider the individual contractor as a central agent of contemporary conflict, identifying three main objections to their deployment: a lack of just cause, virtue and professional legitimacy. Using scholarship on identity work and stigma management more specifically, we analyse contractors’ accounts of their employment to identify the communicative strategies they employ to challenge the stigma attributed to their occupation and/or to them as incumbents. Our data set is memoirs written by five British contractors, published between 2006 and 2011. We also suggest that data such as these are under-utilised in organisation studies’ treatment of identity work, because they represent a distinctive form of this work which we label identity writing.

A comparison of methods to estimate anaerobic capacity: Accumulated oxygen deficit and W' during constant and all-out work-rate profiles

This study investigated (i) whether the accumulated oxygen deficit (AOD) and curvature constant of the power-duration relationship (W') are different during constant work-rate to exhaustion (CWR) and 3-min all-out (3MT) tests and (ii) the relationship between AOD and W' during CWR and 3MT. Twenty-one male cyclists (age: 40 ± 6 years; maximal oxygen uptake [V̇O_2max]: 58 ± 7 ml · kg^-1 · min^-1) completed preliminary tests to determine the V̇O₂-power output relationship and V̇O_2max. Subsequently, AOD and W' were determined as the difference between oxygen demand and oxygen uptake and work completed above critical power, respectively, in CWR and 3MT. There were no differences between tests for duration, work, or average power output (P ≥ 0.05). AOD was greater in the CWR test (4.18 ± 0.95 vs. 3.68 ± 0.98 L; P = 0.004), whereas W' was greater in 3MT (9.55 ± 4.00 vs. 11.37 ± 3.84 kJ; P = 0.010). AOD and W' were significantly correlated in both CWR (P < 0.001, r = 0.654) and 3MT (P < 0.001, r = 0.654). In conclusion, despite positive correlations between AOD and W' in CWR and 3MT, between-test differences in the magnitude of AOD and W', suggest that both measures have different underpinning mechanisms.

McArdle Disease Misdiagnosed as Meningitis

BACKGROUND McArdle disease is a glycogen storage disorder mainly characterized by exercise intolerance. Prolonged muscle contracture is also a feature of this condition and may lead to rhabdomyolysis (RM), which is a serious event characterized by acute skeletal muscle damage.  CASE REPORT A 44-year-old female patient presented with an acute contracture of the posterior neck muscles, causing severe nuchal rigidity. The contracture was induced during a dental extraction as she held her mouth open for a prolonged period, with her neck in a rigid position. She presented with severe pain in her ear and head, as well as fever, vomiting, and confusion. Based on her symptoms, she was initially misdiagnosed with bacterial meningitis and experienced an acute allergic reaction to the systemic penicillin she was subsequently administered. Lumbar puncture results were normal. High serum creatine kinase (CK) levels, recurrent exercise-related muscle symptoms, and a previous history of recurrent myoglobinuria raised the suspicion of an underlying neuromuscular condition. McArdle disease was confirmed by muscle biopsy and a genetic test, which revealed that the patient was homozygous for the R50X mutation in the PYGM gene. CONCLUSIONS This case illustrates that even seemingly innocuous movements, if rapid isotonic or prolonged isometric in nature, can elicit a muscle contracture in McArdle disease patients. Here, we highlight the need for careful management in this patient population even during routine healthcare procedures. The allergic reaction to antibiotics emphasises that misdiagnoses may result in iatrogenic harm.

Genes and exercise intolerance: insights from McArdle disease

McArdle disease (glycogen storage disease type V) is caused by inherited deficiency of a key enzyme in muscle metabolism, the skeletal muscle-specific isoform of glycogen phosphorylase, “myophosphorylase,” which is encoded by the PYGM gene. Here we review the main pathophysiological, genotypic, and phenotypic features of McArdle disease and their interactions. To date, moderate-intensity exercise (together with pre-exercise carbohydrate ingestion) is the only treatment option that has proven useful for these patients. Furthermore, regular physical activity attenuates the clinical severity of McArdle disease. This is quite remarkable for a monogenic disorder that consistently leads to the same metabolic defect at the muscle tissue level, that is, complete inability to use muscle glycogen stores. Further knowledge of this disorder would help patients and enhance understanding of exercise metabolism as well as exercise genomics. Indeed, McArdle disease is a paradigm of human exercise intolerance and PYGM genotyping should be included in the genetic analyses that might be applied in the coming personalized exercise medicine as well as in future research on genetics and exercise-related phenotypes.

Emotionally-intense situations can result in rhabdomyolysis in McArdle disease

Despite the majority of patients with McArdle disease reporting symptoms including fatigue, cramps and episodes of myoglobinuria from early childhood, diagnosis is often delayed by several decades. Additionally, many individuals with rhabdomyolysis remain undiagnosed. The occurrence of symptoms during exercise, particularly isometric muscle contraction such as heavy lifting, is well known in McArdle disease. However, isometric muscle contraction that occurs with emotion is not recognised as exercise and may be missed as a trigger for rhabdomyolysis, potentially leading to a delay in diagnosis. Three patients are presented here, all with symptoms from childhood including episodes of rhabdomyolysis induced by tense emotional situations without physical exertion; two patients reported recurrent episodes while watching rather than playing football. The remaining patient developed rhabdomyolysis during a heated argument. These patients' histories emphasise the risk from sustained isometric muscle contraction that occurs in emotive situations for patients with McArdle disease.

Recurrent rhabdomyolysis due to muscle β-enolase deficiency: very rare or underestimated?

Muscle β-enolase deficiency is a very rare inherited metabolic myopathy caused by an enzymatic defect of distal glycolysis. So far, the condition has been described in only one patient with mutations in ENO3 in a compound heterozygous state who presented with exercise intolerance, post-exercise myalgia and mild hyperCKemia but no pigmenturia. We describe two men, one Italian and one Turkish, with consanguineous parents, who complained of several episodes of intense myalgia, cramps, generalized muscle tenderness and dark urine. No other family members reported similar symptoms. In both cases, there was a very mild rise in lactate during a forearm exercise test. Muscle biopsy showed minimal changes with no lipid or glycogen accumulation. Biochemical studies on muscle tissue demonstrated a marked reduction of muscle β-enolase activity (20 and 10% of residual activity, respectively). Molecular genetic analysis of ENO3 gene revealed two novel homozygous missense mutations, (p.Asn151Ser and p.Glu187Lys). Both mutations segregated as expected in the two families. Although quite rare, muscle β-enolase deficiency should be considered in the differential diagnosis of patients presenting with recurrent rhabdomyolysis. It may present also with a more severe phenotype than previously thought.

From exercise intolerance to functional improvement: the second wind phenomenon in the identification of McArdle disease

McArdle disease is the most common of the glycogen storage diseases. Onset of symptoms is usually in childhood with muscle pain and restricted exercise capacity. Signs and symptoms are often ignored in children or put down to ‘growing pains’ and thus diagnosis is often delayed. Misdiagnosis is not uncommon because several other conditions such as muscular dystrophy and muscle channelopathies can manifest with similar symptoms. A simple exercise test performed in the clinic can however help to identify patients by revealing the second wind phenomenon which is pathognomonic of the condition. Here a patient is reported illustrating the value of using a simple 12 minute walk test.

Soldiering on: Exploring the role of humour as a disciplinary technology in the military

This article considers the role of humour as a disciplinary technology. Using the British military as an organizational context, and drawing on data from the published memoirs of recently serving military personnel, the article makes three arguments in this regard. First, it is argued that the disciplinary apparatus of the military, as an example of a rule-bound and hierarchical organizational structure, creates the conditions that allow for a controlled form of resistance (through humour) to be enacted by organizational subjects; but ultimately, such acts work to serve the requirements of the organization. Second, it is argued that humour contributes to the establishing of social cohesion through disciplinary practices of inclusion and exclusion and the drawing of lines of normalization, both at the local level and at a wider institutional level. Third, it is argued that humour permeates the power relations that structure organizational life: both those governed by rank and position and those that arise through the modes of self-regulation through which much organizational disciplining is enacted. This article concludes by drawing attention to the dialectic and dynamic nature of humour while also offering suggestions for the wider applicability of the disciplinary role of workplace humour.

Challenges in Maintaining Emotion Regulation in a Sleep and Energy Deprived State Induced by the 4800Km Ultra-Endurance Bicycle Race; The Race Across AMerica (RAAM)

Multiday ultra-endurance races present athletes with a significant number of physiological and psychological challenges. We examined emotions, the perceived functionality (optimal-dysfunctional) of emotions, strategies to regulate emotions, sleep quality, and energy intake-expenditure in a four-man team participating in the Race Across AMerica (RAAM); a 4856km continuous cycle race. Cyclists reported experiencing an optimal emotional state for less than 50% of total competition, with emotional states differing significantly between each cyclist over time. Coupled with this emotional disturbance, each cyclist experienced progressively worsening sleep deprivation and daily negative energy balances throughout the RAAM. Cyclists managed less than one hour of continuous sleep per sleep episode, high sleep latency and high percentage moving time. Of note, actual sleep and sleep efficiency were better maintained during longer rest periods, highlighting the importance of a race strategy that seeks to optimise the balance between average cycling velocity and sleep time. Our data suggests that future RAAM cyclists and crew should: 1) identify beliefs on the perceived functionality of emotions in relation to best (functional-optimal) and worst (dysfunctional) performance as the starting point to intervention work; 2) create a plan for support sufficient sleep and recovery; 3) create nutritional strategies that maintain energy intake and thus reduce energy deficits; and 4) prepare for the deleterious effects of sleep deprivation so that they are able to appropriately respond to unexpected stressors and foster functional working interpersonal relationships. Key PointsCompleting the Race Across AMerica (RAAM); a 4856km continuous cycle race associated with sleep disturbance, an energy-deficient state, and experiencing intense unwanted emotions.Cyclists reported experiencing an optimal emotional state for less than 50% of total competition and actual sleep and sleep efficiency was better maintained during longer rest periods.We suggest that future RAAM cyclists and crew should:Identify individual beliefs on the perceived functionality of emotional states in relation to best (optimal) and worst (dysfunctional) performance as the starting point to identifying if emotion regulation strategies should be initiated.Plan for enhanced sleep and recovery not just plan and train for maintaining a high average velocity;Create nutritional strategies that maintain energy intake and thus reduce energy deficits;Psychologically prepare cyclists and crew for the deleterious effects of sleep deprivation so that they both are able to appropriately respond to unexpected stressors and foster functional interpersonal working relationships.

The effects of two weeks of recombinant growth hormone administration on the response of IGF-I and N-terminal pro-peptide of collagen type III (P-III-NP) during a single bout of high resistance exercise in resistance trained young men

OBJECTIVE

Recombinant human growth hormone (rhGH) is used by some athletes and body builders with the aim of enhancing performance, building muscle and improving physique. Detection of the misuse of rhGH has proved difficult for a number of reasons. One of these is the effect of preceding exercise. In this randomised, double blind placebo-controlled study, we determined the effects of rhGH administration in male amateur athletes on two candidate markers of rhGH abuse, IGF-I and N-terminal pro-peptide of collagen type III (P-III-NP), following a bout of weightlifting exercise.

DESIGN

Sixteen men entered a four-week general weight training programme to homogenise their activity profile. They then undertook repeated bouts of standardised leg press weightlifting exercise (AHRET-acute heavy resistance exercise test). Blood samples were taken before and up to one hour after the AHRET. After the first laboratory visit (Test 1), the subjects were randomly assigned to receive daily injections of either rhGH (0.1 IU kg(-1) day(-1)) or placebo for two weeks. The AHRET was repeated after the two-week dosing period (Test 2) and a further test was undertaken following a one-week washout (Test 3).

RESULTS

There was no effect of exercise on either IGF-I or P-III-NP in any test. Both markers were markedly elevated at Test 2 (p<0.001), with P-III-NP remaining elevated at Test 3 in the GH administration group (p<0.05). Application of the GH-2000 discriminant function positively identified GH administration in 17 of 40 blood samples taken at Test 2 from the rhGH group and none from the placebo group.

CONCLUSION

The data show that rhGH results in elevated levels of IGF-I and P-III-NP in well-trained individuals and that leg press weightlifting exercise does not affect these markers. The GH-2000 discriminant function identified four of eight subjects taking rhGH with no false positive results.

The effect of high-intensity aerobic interval training on postinfarction left ventricular remodelling

This is the third in a series of case studies on an individual with normal coronaries who sustained an idiopathic acute myocardial infarction . Bilateral pulmonary emboli almost 2 years post-myocardial infarction (MI) revealed coagulopathy as the cause. The original MI resulted in 16% myocardial scar tissue. An increasing number of patients are surviving MI, hence the burden for healthcare often shifts to heart failure. Accumulating evidence suggests high-intensity aerobic interval exercise (AHIT) is efficacious in improving cardiac function in health and disease. However, its impact on MI scar has never been assessed. Accordingly, the 50-year-old subject of this case study undertook 60 weeks of regular AHIT. Successive cardiac MRI results demonstrate, for the first time, a decrease in MI scar with exercise and, alongside mounting evidence of high efficacy and low risk, suggests AHIT may be increasingly important in future prevention and reversing of disease and or amelioration of symptoms.

The private military industry and neoliberal imperialism: Mapping the terrain

Despite the international reach, and increasing global importance, of the free market provision of military and security services—which we label the Private Security Industry (PSI)—management and organization studies has yet to pay significant attention to this industry. Taking up Grey’s (2009) call for scholarship at the boundaries between security studies and organization studies and building on Banerjee’s (2008) treatment of the PSI as a key element in necrocapitalism, in this article we aim to trace the long history of the PSI and argue that it has re-emerged over the last two decades against, and as a result of, a very specific politico-economic backdrop. We then suggest that the PSI operates as a mechanism for neoliberal imperialism; demonstrate its substitution for and supplementing of the state; and count some of the costs of this privatization of war. Finally, we take seriously Hughes’s (2007) thesis of the growth of a new security-industrial complex, and of the intersecting elites who benefit from this phenomenon.

Biceps, Bitches and Borgs: Reading Jarhead’s Representation of the Construction of the (Masculine) Military Body

This paper explores the relationship between masculinity, the body and the military through a close reading of the film Jarhead. Drawing on a Foucauldian frame of analysis, we consider three performances of the masculine military body that form key aspects of the film’s representational economy: the disciplined body, an outcome of the processes of basic training; the gendered body, realized through deployment of metaphors of the feminine to strengthen the masculine conception of the military body; and the cyborgian body, the result of the man-machine interface which is rapidly developing in many militaries around the world, and which poses significant questions for performances of military masculinity. We conclude by suggesting that the film’s rendering of the material and discursive body reveals an unexpected tension between the expectations of military bodies and the lived experience of their labour. As well as augmenting empirical explorations of male-worker-bodies and analysing the occupation of soldier as requiring a unique kind of body work, our contribution to the body-organization literature turns upon the claim that docile military bodies are made fit for purpose, but may actually no longer have a purpose for which to be fit.

Underlying cause discovered for a prior idiopathic AMI

The authors previously reported on an active, young male with normal coronaries who sustained an acute myocardial infarction (AMI). The acute cause was a coronary thrombus; however, the cause of this thrombus and a definitive diagnosis remained elusive for 18 months until a new series of events, including symptoms of breathlessness, dizziness and collapse led to acute hospital admission. CT scan revealed numerous deep venous thromboses in the right leg and bilateral pulmonary emboli (PE). Acute pharmacological thrombolysis eliminated breathlessness and significantly reduced the risk of mortality. Clinical consensus suggests a coagulopathy, requiring indefinite treatment with Warfarin. In young individuals presenting with AMI, lifestyle, personal, family and clinical history should be considered and coronary artery disease should not be assumed until further tests have eliminated coagulopathy. In those presenting with breathlessness and a history which includes AMI, a CT scan is indicated to eliminate concerns of venous thromboembolism generally and PE specifically where untreated survival times are short.

Diverse patterns of myocardial fibrosis in lifelong, veteran endurance athletes

This study examined the cardiac structure and function of a unique cohort of documented lifelong, competitive endurance veteran athletes (>50 yr). Twelve lifelong veteran male endurance athletes [mean ± SD (range) age: 56 ± 6 yr (50-67)], 20 age-matched veteran controls [60 ± 5 yr; (52-69)], and 17 younger male endurance athletes [31 ± 5 yr (26-40)] without significant comorbidities underwent cardiac magnetic resonance (CMR) imaging to assess cardiac morphology and function, as well as CMR imaging with late gadolinium enhancement (LGE) to assess myocardial fibrosis. Lifelong veteran athletes had smaller left (LV) and right ventricular (RV) end-diastolic and end-systolic volumes (P < 0.05), but maintained LV and RV systolic function compared with young athletes. However, veteran athletes had a significantly larger absolute and indexed LV and RV end-diastolic and systolic volumes, intraventricular septum thickness during diastole, posterior wall thickness during diastole, and LV and RV stroke volumes (P < 0.05), together with significantly reduced LV and RV ejection fractions (P < 0.05), compared with veteran controls. In six (50%) of the veteran athletes, LGE of CMR indicated the presence of myocardial fibrosis (4 veteran athletes with LGE of nonspecific cause, 1 probable previous myocarditis, and 1 probable previous silent myocardial infarction). There was no LGE in the age-matched veteran controls or young athletes. The prevalence of LGE in veteran athletes was not associated with age, height, weight, or body surface area (P > 0.05), but was significantly associated with the number of years spent training (P < 0.001), number of competitive marathons (P < 0.001), and ultraendurance (>50 miles) marathons (P < 0.007) completed. An unexpectedly high prevalence of myocardial fibrosis (50%) was observed in healthy, asymptomatic, lifelong veteran male athletes, compared with zero cases in age-matched veteran controls and young athletes. These data suggest a link between lifelong endurance exercise and myocardial fibrosis that requires further investigation.

Emotional and cognitive changes during and post a near fatal heart attack and one-year after: a case study

This case study reports on changes in emotions before and during an unexpected heart rate in a young, apparently healthy male with a life-long history of exercise in the absence of family history of heart problems. He completed the Brunel Mood Scale (Terry et al. , 2003) to assess emotions before, during, and after the heart attack, and also describing his thoughts during these periods. Results indicate he experienced unpleasant emotions in the build up to the heart attack, feelings he attributed at the time to frustration to achieve fitness goals. He maintained an exercise regime prior to having a heart attack, a finding consistent with previous research suggesting that early diagnosis, although vital for survival, is not likely to be identified among seemingly healthy individuals. During the heart attack, he experienced a rapid emotional change characterised by a rapid increase in anger coupled with thoughts of needing to survive. The intensity of emotions and regulation strategies employed before and during the heart attack provide insight this experience, and we suggest future research should investigate emotional change during adverse conditions. Key pointsThe present case study details emotions experienced and attempts to regulate these emotions before, during and post a heart attack. Unpleasant emotions experienced before the heart were attributed to lack of progress toward fitness goals, a perception that is plausible as he was a regular exerciser.Early identification of heart attack is critical as "Time is Muscle" (Whyte et al., 2009) and therefore even people perceived to be at low risk should consider the possibility of such an eventuality, and seek medical treatment early in the process.

Troponin release following endurance exercise: is inflammation the cause? a cardiovascular magnetic resonance study

BACKGROUND

The aetiology and clinical significance of troponin release following endurance exercise is unclear but may be due to transient myocardial inflammation. Cardiovascular magnetic resonance (CMR) affords us the opportunity to evaluate the presence of myocardial inflammation and focal fibrosis and is the ideal imaging modality to study this hypothesis. We sought to correlate the relationship between acute bouts of ultra endurance exercise leading to cardiac biomarkers elevation and the presence of myocardial inflammation and fibrosis using CMR.

METHODS

17 recreation athletes (33.5 +/- 6.5 years) were studied before and after a marathon run with troponin, NTproBNP, and CMR. Specific imaging parameters to look for inflammation included T2 weighted images, and T1 weighted spin-echo images before and after an intravenous gadolinium-DTPA to detect myocardial hyperemia secondary to inflammation. Late gadolinium imaging was performed (LGE) to detect any focal regions of replacement fibrosis.

RESULTS

Eleven of the 17 participant had elevations of TnI above levels of cut off for myocardial infarction 6 hrs after the marathon (0.075 +/- 0.02, p = 0.007). Left ventricular volumes were reduced post marathon and a small increase in ejection fraction was noted (64+/- 1% pre, 67+/- 1.2% post, P = 0.014). Right ventricular volumes, stroke volume, and ejection fraction were unchanged post marathon. No athlete fulfilled criteria for myocardial inflammation based on current criteria. No regions of focal fibrosis were seen in any of the participants.

CONCLUSION

Exercise induced cardiac biomarker release is not associated with any functional changes by CMR or any detectable myocardial inflammation or fibrosis.